Fluid pressure device and system



Sept 16, 1.941- c. M. E|-1DRI -1K 2,255,783

FLUID PRESSURE DEVICE AND SYSTEM #fea/7x for Vary/'ng ar// Tonk :L *i

INVENTOR Sept. 16, 1941. c. M. KENDRICK 2,255,783

FLUID PRESSURE` DEVICE ,-AND, SYSTEM v f Filed Feb. 17, 1940 4 Sheets-Shes?l 2 7o decrease Pump el I 62 76 BY S,

Sept. 16, 1941. c. M. KENDRICK 2,255,783

FLUID PRESSURE DEVICE AND SYSTEM I Filed Feb. 17, 1940 4 sheets-sheet 3' Sept. 1 6, 1941. c. M. KENDRlcK FLUID PRESSURE DEVICE AND SYSTEM Filed Feb. 1'7, 1940 4 Sheets-Sheet-l two pressures Patented Sept. 16, 1941 FLUID PRESSURE DEVICE AND SYSTEM Charles M. Kendrick, New York, N. Y., assigner to Manly Corporation, Washington, D. C., a corporation of Delaware Application February 17, 1940, Serial No. 319,399

25 Claims. (Cl. 60-53) This invention relates to fluid pressure devices and systems which are adapted to transmit power by means of fluid under pressure and more particularly to devices and systems of this character which include a vane type fluid motor in which the vanes are urged into contact with the vane track by fluid pressure means.

The widest present use for devices and systems of this general class is as hydraulic devices and systems, that is to say, devices and systems for handling, or whose motive fluid is a liquid, such for exam-ple, as oil. The present invention will accordingly be described in connection with such vuse although it will be understood that the invention is also applicable to devices and systems operating with elastic fluids.

Vane type motors of the character mentioned above include a vane track that surrounds the rotor and vane assembly. For quiet and satisfactory operation of the motor it is practically essential that the outer ends of the vanes be urged into contact with the vane track when operation of the motor is started and that such contact be maintained continuously during its operation. In order to provide this track-contacting and track-following'action of the vanes it is necessary to supplement the action of centrifugal force with an auxiliary force acting to urge the vanes outward, at least during the portion of their rotary travel in which they are passing through the intake area or areas of the motor, so that the outer ends of the vanes will be held firmly in contact with the surrounding vane track and thus provide a movable resistance to the pressure fluid admitted to the outer ends fully explained in my co-pending application led vMarch 28, 1938, Serial Number 198,449. Thus fluid under two different but related operating pressures is used; the fluid having the higher of these two pressures, which for convenience is termed the differential high pressure fluid, is admitted to the radially inner ends of the vanes, while fluid under the lesser of these (for convenience working pressure fluid or operating pressure fluid) is admitted lto the pressure areas at the outer ends of the vanes of the Vane motor. In the fluid pressure device and system of the present invention these two different but related pressures are obtained-by passing the supply of fluid going to the motor through "differential pressure or resistance valve mechanism' positioned in the fluid inlet conduit.

When the vane type motor is of constant capacity (i. e. constant fluid capacity or displacement per revolution of its rotor) its speed'or operation or rotation is controlled by regulating the volume of operating pressure fluid supplied to the outer ends of its vanes. 'I'he speed of a variable capacity vane motor may also be regulated by altering the capacity or displacement per revolution of the rotor thereof, but the torque of the motor will then vary substantially inversely with the speed of rotation so that in all events the volume of operating pressure fluid, at any given pressure thereof, supplied to the outer ends of the vanes determines the power that is transmitted by the vane motor.

An object of the bresent invention is to provide an improved, simple and economical fluid pressure device and system including a vane type fluid motor and employing unitary means for performing the dual functions of controlling the speed of the motor by regulating the volume of operating pressure fluid supplied to the outer ends of the vanes of the motor and of providing fluid, at a different pressure but related to the pressure of the operating fluid supplied to the outer ends of the vanes, for urging the vanes of the motor outward into contact with the Vane track.

Another object is to provide a fluid pressure device and system of the character above set forth, and in ,which the volume `of operating pressure fluid supplied to the outer ends of the vanes and the difference in pressures of the operating pressure fluid and the fluid supplied for urging the vanes into contact with the vane track are held substantially constant independent of the load that is imposed on the vane motor and the consequent pressure of the operating fluid resulting from such load.

A further object is to provide such a fluid pressure device and system in which the volume ofoperating pressure fluid supplied to the outer ends of the' vanes. is held substantially constant independent of change in viscosity of the circulated fluid, and further, by which the volume termed the of operating pressure fluid and the difference in 4pressures between the operating pressure fluid and the differential high pressure fluid going to the .inner ends of the vanes may bothrbe held substantially constant irrespective of viscosity changes.

A still further object is to provide a fluid pressure device and system `of the character above set forth which also includes a variable output pump and in which unitary means are employed for regulating the output of the pump and for providing the supply yof fluid active to urge l the vanes of the vane type motor into contact with 'its vane track.

Other and more specific objects will appear tor will be presumed to be employed in all emthe invention in which means are provided to compensate for change in viscosity of the circulated fluid;

Fig. 3 is a fragmentary diagrammatic view,

partly in section, showing a modification including a constant capacity or output pump and relief valve means for the escape of pressure fluid, which may be substituted for the variable output pump of both Figs. 1 and. 2;

Fig. 4 is another. diagrammatic view, partly in section, ilustrating another modification which also includes a pump of constant capacity or output;

Fig. 5 shows la modification of alternative viscosity compensating means;

Fig. 6 is alongitudinal sectional View, taken along the line 6-6 of Fig. 7 of an illustrative embodiment ofthe vane type motor forming part of the fluid pressure device and system of the present invention;

Fig. 7 is a view in vertical section transverse Y' the axis of rotation of the vane type motor and taken along the line 'I-I of Fig. 6;

Fig. 8 is also a vertical transverse section but with the shaft removed and is taken along the line 8-8 of Fig. 6, looking in a direction opposite to that of Fig. 7;

Fig. 9 shows an inner elevation of one of the members of the vane motor, for convenience termed an end plate or cheek plate; and

Fig. 10 is a sectional view of the cheek plate, taken along the line IU-I 6 of Fig. 9. A

As shown in Figs. 1, 2 and 4, the fluid pressure device and system of the present invention includes a vane type motor B. The motor B l may be of either constant or variable capacity or displacement per revolution of its rotor, but for purposes of illustration I have chosen a constant capacity vane type motor in which the 'i vanes move inward and outward with respect to the rotorin a generally radial direction; this illustrative motor forms no part per se, however, i ofthe present invention but a part of co-pending application filed March 28, 1938, Serial Number 198,449 and certain features of its construcbodiments illustrated in the accompanying draw- 'ings and will accordingly be first described.

-ward and outward in the van-e slots I6 (Fig. 6).

A vane track ring 25 surrounds the rotor andI vane assembly and its inner circumferential surface 26 forms a track adapted to contact the radially outer ends of the vanes I'I as the rotor revolves and to guide and control the vanes in vtheir inward and outward movement; the surface 26 will hereinafter be refered to as the Vane track. v

The rotor I5 and driven shaft 20 may be mounted and the two parts may be operatively connected with each other in any appropriate manner. In th-e present instance the rotor l5, shaft 26, their mountings and the operative connection therebetween are th same as `disclosed in co-pending application filed December 6, 1939, Serial Number 307,755. As shown in Fig. 6. the shaft 20 is revolubly supported by a pair of bearing elements 23 and 24 carried by the casing I0 and the rotor I5 is supportedly mounted on the end of the shaft 26 which projects into the rotor cavity. For this purpose the end of the shaft 20 is formed with axially extending splines 2| (Figs. 6 and 7) 'and the rotor I5 is formed in its central opening with mating splines I8. The arrangement is such that the rotor I5 is freely movable in an axial direction on the shaft splines2I while also permitting a limited angular or rocking motion of the rotor I5 relative to the shaft 20 in such maner that the cheek plates 34 and 35, to be presently described, determine the axial and angular position of thel rotor on the shaft and the plane of rotation of the rotor as fully explained in co-pending application Serial Number 307,755 above mentioned.

The rotor I5 is hydraulically balanced with respect to all forces imposed thereon by'fluid pressure. the rotor in a radial direction is obtained by dividing the space intermediate the periphery of the rotor I5 and the vane track 2'6 into two equal and oppositely positioned fluid sections, each fluid section comprising a working chamber flanked by an inlet area and an outlet area. As shown in Fig. 7, the division between the two fluid sections is effected by co-operation of the rotor I5 and the outer ends of the vanes I'I with the vane track 26 at the regions of the vane tracks least diameter which in the present embodiment isl adjacent the horizontal centerline. The vane track 26 is preferably provided at each of these points of division with an arc 2I, for convenience termed the "sealing arc, substantially concentric with the rotor I5 and extending in a circumferential direction for a distance equal to at least the angular distance between a pair of adjacent vanes I'I.

The working chambers of the two fluid sections are formed by means of two diametrically positioned arcs 3|, preferably concentric with the rotor I5 and termed "working arcs, which are located in the regions of greatest diameter ofthe vane track 26. The working chambers Hydraulic balance of forces acting on extend in a circumferential direction for an arcuate distance substantially equal to the distance between the outer ends of two adjacent vanes I1v which at any given instant are moving in contact with the working arcs 3l. .Operating pressure fluid is admitted between the vanes as they .move through the inlet areas toward the working chambers and fluid is discharged as the vanes recede therefrom through the outlet areas of the two fluid sections. The inlet area of each fluid section is thus at all times separated from the outlet area of the same fluid section 'by at least one of the vanes I1 and the difference in pressures on the opposite sides or faces of such vane or vanes causes rotation of the rotor I5, which in the present instance 'is inl a clockwise direction as viewed in Fig. '1. The portions of the vane track 26 intermediate the sealing arcs 21 and working arcs 3| may be given any suitable curvature producing satisfactory rates of inward and outward movement of the vanes I1 as the rotor I5 revolves. v

The sides or axial ends of the working chambers are closed by a pair of mating disc-shaped members 34 and 35 (Figs. 6, 7, 9 and 10), for 25 convenience termed end plates or cheek plates, which are provided with holes at their centers for/the shaft 2li.. The outer surfaces of the cheek plates 34 and 36 fit snugly against the wall surfaces of the casing I0 and end head iI respectively and form substantially iluid tight fits with the several ports and passages to Abe presently described. The inner or opposing faces of the cheek plates 34 and 35 form fluid tight fits with the sides of the vane track ring by which they are axially positioned with respect to the rotor I5 in suchmanner that the rotor is permitted to turn freely while its sides and the sides of the vanes I1 form substantially fluid tight `running fits with the adjacent faces of the cheek plates 34 and 35. The cheek plate 34 will hereinafter be termed the casing cheek plate and the cheek plate 35 will be termed the end head cheek plate.

I'he cheek plates 34 and 35'are each provided with co-extensive mating ports (Figs. 6, '1 and 9), the ports of one cheek plate being axially opposite the ports of the other cheek plate when' the parts are in position in the casing II) so that all forces exerted upon the rotor I5 and vanes I1 in an axial direction by uid pressure are thus completely balanced. Theports in the cheek plates 34 and 35 will be best understood from Figs. 9 and 10, in which Fig. 9 shows an inner elevation or the rotor face of the end head cheek plate 35. Referring to Fig. 9, each cheek plate is1 provided with a pair of diametrically .opposed arcuate inlet slots or ports 36 and a similar pair of diametrlcally opposed outlet slots or ports 31; these ports are also partially shown in Fig. 7 and the inlet ports 36 areshown in the sectional view of Fig. 6 and the outlet ports 31 are shown in section in Fig. l0. .Operating pressure fluid is admitted to the outer ends of, the vanes I1 through the inlet ports 36 of theA casing cheek plate 34, and, similarly, fluid discharged or exhausted by said vanes passesout through the outlet ports 31. of the same cheek supply of fluid (whichl isA received through the.V4 'vaneslots I6)- llavingfthev same pressure as the provided with twoxpairs of arcuate recesses or vane slot ports 38 and 39 in the faces thereof adjacent the rotor l5 as best shown in Fig. 9; the vane slot ports 38 are, however, also shown in the Asectional view of Fig. 6'and the vane slot ports 39 are likewise shown in the sectional view of Fig. 10. These vane slot ports 38 and 39 are positioned to register successively with lthe inner ends of the vane slots I6 as the rotor revolves and the vane slot ports of each pair are positioned diametrically opposite each other. The arrangement is such that the inner end of each vane slot I6 connects with one of the vane slot ports 38 while the vane I1 therein is pass-v ing through the inlet area of each fluid section and also While traversing the sealing arcs 21 and working arcs 3l. The arrangement is lalso such that the inner'end of each vane slot I6 connects with one of the vane slot ports 39 while the'vane in said slot is passing through the outlet area of each fluid section; the vane slot ports 39, preferably of both cheek plates 34 and 35, are connected with the corresponding outlet ports 31 by radial grooves 32 formed on the outer faces of said cheek plates, as indicated by dotted lines in Fig. 9 and shown in the sectional view of Fig. 10.. In this manner fluid discharge by the inner ends of the vanes passes out through the outlet ports of the casing cheek plate 34.

As already stated, in order for the motor B to operate quietly and smoothly it is necessary to supplement the action of centrifugal force with an auxiliary force urging thevanes I1 into contact with the vane track 26 during 'at least the portion of their rotary travel in which the outer ends of said vanes are. passing through the inlet areas of the motor. This is accomplished by introducing behind the i'nner ends of the vanes, through the vane slot ports 38, pressure fluid (hereinafter termed the differential high pressure iluid) having a pressure greater than but correlated with the .pressure of the operating pressure fluid supplied to the inlet areas ofthe motor B where it acts upon the exposed outer ends of the Ovanes, as fully explained in end ofone `of the two passages I3 formed inv the end head II. The outer ends of the passages I3 connect with a passage I4 which inturn is appropriately connected with a conduit 45 through which differential high pressure fluid is supplied, said differential high pressure fluid being obtained in amanner to be presently explained. The vane slot ports 38 of the casing cheek plate 34 are not directly connected with the differential high pressure fluid supply and act principally as balance ports to contain a fluid in'they'ane slot ports 38 ofK the end head cheek plate 35, in order to substantially balance.

. the hydraulic forces acting on the sides or axial plate.y 'I'he ports 36 and 31 of the end head cheek plate 35 function principallyv as balance ports to contain fluid under the same pressure as that in the corresponding ports of. the casing.

cheek plate 34 in order to produce hydraulic balance of the rotating parts, as alreadystated. A Each of the cheek plates 3 4 `and 35 is also ends of the vanes I1 androt vent binding of the parts.

The fluid circuit of the Vmotor B: also includes 'r I5 and thus prea branched fluid inlet channel 149 (Figs. 6 and) I and a branchediluid outlet channel 4I which are similar to the fluid chnnelsshown in application .Serial Number 307,755 and Iboth of which are formed in the casing' l0. Ihe iluidin- Each g4 Ilet channel 46 is appropriately connected with the fluid supply conduit 42 and is also connected lwithl the fluid inlet ports 36 of the casing cheek plate 34 as by the slanted passages` 44 shown in Fig. 6. connected with the outlet or exhaust conduit 43 and .with the outlet ports 31 in the casingA cheek plate 34 by slantedpassages, not shown, similar The fluid outlet channel 4| is similarly `to the slanted passages 44.

In the fluid pressuredevice and system illus- `trated in Fig. 1, the motor B is operated by fluid Idelivered bya variable delivery pump A, the output of which may be infinitely varied from minimum (such as zero) to maximum to produce corresponding speeds of the .motor B. 'Ihe pump `A receives its supply of fluid through an inlet conduit. 46 from a reservoir or tank 41 and fluid pumped by the pump A is discharged into the conduit' 42 with which' said pumpn A is appropriatelf connected.

The volume of fluid delivered per revolution or other unit of movement of the driving ele` ment of the pump A is controlled in the embodiment shown by the position of a laterally movable adjusting rod or volume-determining element 46. The arrangement is such that movement of the adjusting rod 48 inward, or toward the right as viewed in Fig. 1, causes decrease in the delivered volume, while its movement outward, or toward the left, causes increase in said delivered volume.

The adjusting rod 46 is moved and its position controlled by power actuated means in cooperation with control mechanism. The power actuated means in this instance is a fluid motor which includes an adjusting piston 56 reciprocable in an adjusting cylinder 5| and operatively connected with the adjusting rod 48, as indicated at 49, for simultaneous movement therewith. 1 Movement of the adjusting piston 56, and hence its position, is controlled by `admission of pressure fluid to one end of the adjusting cylinder 5| and simultaneous exhaust of uid from thev other end thereof under control of valve mechanism. The valve and associatedpump output control mechanism illustrated in Figs. 1 and 2 are similar to those disclosed and claimed in co-pending application Serial Number 207,512, filed May 12, 1938, since issued as Patent No. 2,238,061. Referring to Fig. 1, the ends of the adjusting cylinder 5| are suitably connected, as by passages 53 and 54 respectively, with a pair of annular cylinder'ports 51 and58 in the bore 56 of the valve housing 55,'the valve bore 56 being appropriately closed at both its ends. Ad-

mission and exhaust'of uid to and from the v ends of the adjusting cylinder 5| are regulated by a valve piston slidable withinthe valve bore 56 and nprovided with a pair of heads 6| and 62 which. are' separated by a reduced portion 63.

LThe arrangement is such that' the heads 6| and 62 cover the cylinder ports 51 and 58 respectively when the valve piston 66 is in its neutralposition in which it is shown in Fig. 1 and which said heads Gland 62 cut oflj all communi- .cation between the ends of the adjusting-,cyl-

inder 5| and the valve bore 56, so that the adjusting piston 56 is rendered inoperative. Movement ofthe valve piston 66 away from its neutral position and toward the right as viewed in Fig. 1 causes the adjusting piston 66 to move outward or toward the left; and similarly, movement of the valve piston 36 away from its. neu'- -tral `position and toward the' left willause the adjusting. piston to move inward, or toward the right;

In the embodiment of the invention illustrated in Fig. 1, the differential high pressure fluid for urging the vanes |1 of the motor B into contact with the vane track 26 thereof is obtained by providing in the conduit 42 a variable orice 16,. the resistance to flow through which creates the difference in pressures between the differential high pressure fluid going to the inner ends of the vanes |1 and the operating pressure fluid going to the outer ends of said vanes. 'Ihe conduit 45 is accordingly connected with the conduit 42 at a point on the inlet side of the orifice 16, that is, at a point intermediate the pump A and said orifice. The output of the pump A is regulated to provide the proper volume of fluid to produce a predetermined pressure drop across the variable orifice 16, for any extent of opening thereof, so that the difference in pressures between the differential high pressure fluid and the operating pressure flujd is held substantially 4, constant, and change in output of the pump A is made responsive to the pressure drop actually existing across said orifice 16 relative to the predetermined pressure-drop thereacross.

In order that the output of the pump A may be regulated and varied responsive to the pressure drop across the variable orifice 10, the opposite ends of the valve piston 66, which are of equal area, vare adapted to be acted upon by fluid from the inlet and outlet sides respectively of the orifice 10. The opposite ends of the valve bore 56 are accordingly supplied with fluid from the inlet and outlet sides respectively of the orifice 16, as by the passages 12 and 13 which enter said valve bore 56 at points intermediate its closed ends and the ends of the valve piston 60. With this arrangement, pressure fluid from the inlet side of the orifice '|6 entering the right hand end of the valve bore 56 exerts a force upon l the .valve piston 66 tending to move it toward the leftl as viewed in Fig. 1, this force being opposed by the action of pressure fluid from' the outlet side of the orice 16 upon the lleft hand end of the valve piston 66 which tends to move said valve piston toward the right.

The force exerted upon the valve piston 66" 'by pressure fluid from the outlet side of the orifice 16, that is, the force tending to move the valve piston 66 toward the right, is supplemented by force exerted by a compression spring 64 positioned in the left hand of the valve bore 56-. One end of the spring 64 bears against the adjacent end of the valve piston 66 and its other end bears :against an abutment Ipiece 65 disposed intermediate the end of said springs 64 and the endu of a screw 66 which extends through the closed en d of the valve bore 56 and provides means by which the compression of the spring 64 may be adjusted. The force exerted by the vspring 64 thus combines with the fluid-exerted force tending to move the valve piston 66 to- .Ward the right and together they act to oppose and balance the single force exerted upon said valve piston 66 by fluid from the inlet side of the orifice 16, as will be more fully explained presently.

With the parts in the position shownln Fig. 1 and the pump A continuously driven, pressure fluid delivered by-said pump into the conduit 42 passes therethrough to the motor` B which is operated thereby, differential high pressure fluid from the `inlet side -of the orifice 16 going to the inner ends of the motorvanes |1 through the .from the outlet vside of said orifice.

conduit 45 and operating pressure uid from the outlet side of the oriiice 10 going to the outer ends of said motor vanes l1. The parts of the control and -adjusting mechanism will lremain in the position shown in Fig. 1 whenever the output of the pump A is such that it produces a pressure drop across the orifice 10 of such an amount that the force exerted upon the valve piston 60 by fluid from the inlet side of the orifice 1U equals the combined opposing forces exerted by the spring 64 and the pressure fluid With the viscosity of the fluid constant or neglected for purposes of explanation, it will thus be understood that the pressure drop across the orifice 10 (for any setting or adjustment of size of said orifice and of compression of the spring 64) will ldepend entirely upon the rate of fluid flow therethrough. It will also be understood that the valve piston 60 will remain in its neutral position of Fig. 1 as long as the output of the pump A remains constant at an amount producing the pressure drop across thel orifice '10 required to balance the force exerted by the spring 64. The pressure of the differential high pressure fluid will therefore exceed the pressure of the operating pressure iiuid by a substantially constant amount whenever the valve piston 60 is in its natural position and the speed of the motor B will likewise be held substantially conforces exerted by the spring G4 and the pres-y sure fluid from the outlet side of said orifice 1B. The valve piston 60 will thus be immediately displaced from its neutral position and moved toward the left as viewed in Fig. 1. This movement of the valve piston 60 connects the cylinder port 58 with the right hand end of the valve bore 56, permitting pressure fluid to pass to the outer end of the adjusting cylinder 5I; the cylinder port 51 is simultaneously connected with the portion of the valve bore 56 surrounding the valve `pistons reduced portion 63, permitting exhaust of fluid from the inner end of the adjusting cylinder 5| into this portion of the valve bore and thence through the passage 59 to the reservoir 41. Pressure fluid acting upon the outer end thereof will immediately move the adjusting piston 50 in an inward or delivery-decreasing direction, thus reducing the output of the pump A.

The pressure drop across the orice 10 will 'l decrease conformably with and immediately upon decrease in the output of the pump A. Re-

sponsive to this decrease in pressure drop, the

valve piston 60 will be correspondingly and i' simultaneously moved toward the right as viewed in Fig. 1. Decrease in the output of the pump A, accompanied by corresponding decrease in the speed of the motor B and corresponding movement of the valve piston 60 toward the right, will continue untilv the delivered volume is reduced` to the exact amount producing the pressure drop across the orifice 'l0 as established by the spring 64, when the valve piston 60 will be restored to its neutral position and will again render the adjusting piston.50 inoperative; the speed of the motor B will likewise be correctively altered and the pressure difference between the differenti-al high pressure fluid `and t operating pressure fluid will also be restored tgethe amount as determined by the spring 64.

The operation of the mechanism is the reverse of that explained when the output of the pump A is for any reason decreased below the amount at which the corresponding pressure drop across the orifice 'I0 produces balance of forces acting upon the valve piston 60 in its neutral position; that is, whenever the dilerence between the pressures of the diierential high pressure uid and the operating pressure iluid drops below the amount determined by the spring 64, with corresponding decrease in the speed of the motor B. Immediately upon such decrease in the pressure drop, the valve piston 60 is moved toward the right as viewed in Fig. 1, pressure fluid is admitted to the inner end of the adjusting cylinder 5I and the outer end thereof will be connected with the exhaust, so that the adjusting piston 50 will be moved outward or in'a delivery-increasing direction until the output of the pump A is increased to an amount producing the predetermined pressure drop across the orifice l0, thereby providing the predetermined dierence in pressures between the differential high pressure iiuid and the operating pressure uid, as determined by the spring 64 and causing the operation of the motor B at the speed corresponding to the exent of opening of the orice 10. Upon these corrective changes, the valve piston 60 will again be restored to its neutral position of Fig. 1.

These corrective changes in both increase and decrease of 'the pumps output and restoring movements of the valve piston 60 take place almost instantaneously, and the adjustmentsare such as to set the corrective mechanism into operation upon slight changes in the pressure drop to be maintained across the orifice 10.

It will thus be seen that the spring 64 determines the amount of the .pressure drop to be maintained across the orifice 10 and hence the difference in pressures between the differential high pressure fluid and the operating pressure fluid; the valve piston B0 being moved in one direction or the other to eiect corrective change in the pumps output whenever the pressure drop across this orifice is either greater or less than the corresponding force exerted upon the valve piston 60 in its neutral position by the spring 64. The compression of the spring 64 is accordingly adjusted to provide a pressure drop across the orifice 10 such that the differential high pressure iiuid from the inlet side of said orifice 10 exceeds the pressure of the operating pressure fluid from the outlet side of -said orifice by an amount suf- .fcient to provide satisfactory action of the motor vanes I1. Position and'movement of the valve piston 60 are determined and effected entirely by relative pressures existing on the inlet and outlet sides respectively of the orice 10 and are independent of absolute pressures; that is to say, the valve pistons movement and position result from the difference between these pressures regardless of 4their actual amount so that the differential high pressure fluid is kept at a pressure or pressures exceeding by a substantially constant amount the pressure or pressures of the operating fluid, regardless of the amount of or change in the pressure of said operating pressure uid, and the inner ends of the motor vanes I1 are thus supplied with fluid at a pressure greater than but correlated with the pressure of the fluid admitted to the outer ends thereof.

The speed of the motor B is regulated by varying the size or extent of opening yof. the variable orifice 10, .as by the means 1l schematically shown in Fig. 1. Change in the size or extent of opening of the orifice 1U will, of course, change the volume of fluid required to pass therethrough to produce the pressure drop as established by the spring 64. An infinitely variable orifice, such as here provided, thus makes it possible to infinitely vary the pumps output to any desired extent from maximum to a minimum, such as zero, and to correspondingly vary the speed of the motor B. At all outputs of the pump A and at all speeds of the motor B, the dilerential high pressure fluid will exceed in pressure by a substantially constant amount, as determined by the spring 64, the pressure of the operating pressure fluid admitted to the outer ends of the motor vanes I1, and the maximum size or extent of opening of the orice 10 is preferably made such that the corresponding pressure drop thereacross pro# duced by the maximum output of the pump A will provide a suificient difference in pressure to assure satisfactory action of said motor vanes I1.

No uid will be available for moving the adjusting piston 5U to start delivery of fluid by the pump A when the output lthereof is reduced to zero. The inner or piston rod end of the adjusting cylinder 5| is accordingly provided with a spring 68, one end of which acts against thel adjacent end of the adjusting piston 60 andthe other end of which acts against the' cover 52 l which closes the end of the adjusting cylinder 5I. The arrangement is such, preferably, that the spring 68 is compressed as the adjusting piston 58 moves into its position corresponding to the zero output position of the adjusting rod 48. The energy thus stored up is avaliable for displacing the adjusting piston 50 and adjusting rod 48 from their zero output positions so that the pumpy may be caused to start delivery of pressure iiuid.

In the embodiment illustrated in Fig. 1, the output of the pump A will be varied, upon any change in its speed or increased leakage in said pump, to hold the volume of fluid delivered to the outer ends of the motor vanes l1 substantially constant, and hence to hold the 'speed of the motorsubstantially constant, for any extent of opening of the orifice 10 provided the', viscosity of the circulated fluid remains constant. Lubrieating oil is usually employed as the circulated fluid in systems of this charac-ter, and is subject to relatively large changes in viscosity as its temperature changes. Such viscosity changes alter the resistance to ow through the orifice 18 and therefore noticeably'l affect thel volume of fluid that is permitted to pas'sytherethrough (for any given opening of said' orifice 10 and any given adjustment of the spring 64A). which in turn causes corresponding change in th'e speed of the motor B unless means are provided to compensate vfor such viscosity changes. Such viscosity compensating means are provided :in4 the embodiment illustrated in Fig@ and'will now be described.

The arrangement of Fig. 2 istgenerally similar to the embodiment of Fig. 1 exceptfor the provision of the viscosity compensating mechanism. The valve mechanism includes a valve piston 60' pair of heads 6l and 62' which are adapted to spectively when said valve piston is in its 'neutral position in Which it is shown in Figi 2. The valve piston 68' also includes a pair of extension rods 11 and 18, of `equal diameter, which extend from the heads 6|' and 62' respectively and project `through suitable openings in the closures of the ends of the valve bore 56 in such manner that they form substantially iiuid tightfits therewith. The ends of the adjusting cylinder 5I are connected with the cylinder ports 51 and 58 respectively by the passages 53 and 54 and the portions of the valve bore surrounding the valve rods"11 and 18 respectively are connected with the inlet and outlet sides respectively of the orifice 10 -by the passages 12 .and 1-3 which are shown as constricted at 12 and 13 at the valve bore 56 in order to reduce any tendency'toward hunting or chatter. The spring 64' in the left hand end of the valve bore 56' surrounds the valve rod 11 and exerts a force on the valve piston 69 tending to move it toward the right, as in the embodiment of Fig. 1. It will thus be seen that this portion of the valvemechanism is substantially identical with that of the embodiment of Fig. 1 from which it differs, as described up to this point, principally With respect to the provision of the valve rods 11 and 18. This portion of the mechanism is therefore capable of operation in the same manner as described in linstance are formed in the members 15 and 16 vwhich close the ends of the Valve bore 56".

The compensating cylinders are provided with slidably fitted pistons, termed compensating pistons, operatively connected with the valve piston 60 and the ends of the rods 11 and 18 are utilized as the compensating pistons. in the present embodiment. Each compensating piston is of such size that its cross-sectional area equals the cross-sectional area of one of the portions of the valve` piston 60' which are exposed to the pressu're uid in the ends of the valve bore 56', that is to say, the cross-sectional area of each compensating piston'equals thel cross-sectional area of the head 6I', or 62', minus the cross sectional area of the corresponding rod 11 or 18; this relation is here obtained by making the rods 11 and 18 of such size that the cross-.sectional area of each of them is one-half theAv area of a section through the heads 6| or 62 of thefvalve l piston 66.

The viscosity compensating mechanism also includes an auxiliary fluid circuit, which may be termed the compensating circuit, which in turn or fluid supply conduit 46 of the main pump A.

It will thus be seen that the uid supplied to the pump 83 will at all times be of exactly the same viscosity'as thefluid supplied to the main pump slidable within the b ore 56 and provided with a A, and hence of the same viscosity as that of the fluid passing through the orifice 10. The pump 83 is also provided with a.4 discharge conduit 85 `leading to the reservoir 41 and having an orisame viscosity as the fluid passing through the orifice 10, it will be seen that change in viscosity of the circulated fluid will produce identical changes in the amounts of the pressure drop across both orifices for constant rates of flow through them. The rate of fluid flow through the orifice 86 is constant for the reason that the orifice 16 produced by a constant output of the pump A and therefore reduces the net difference or resultant of the forces exerted upon the valve piston 66' by fluid from the inlet and outlet sides of the orifice 10, which net difference or resultant tends to` move the valve piston 68' toward the left ;v this decrease in viscosity simultaneously also reduces, by exactly the same amount, the sum of the combined opposing forces which tend through action of the compensating pistons to move the valve piston 66 toward the right. In the same manner, increase in viscosity of the fluid simultaneously and equally increases pump 83 is of constant capacity and is driven at constant speed. Hence the change inthe pressure drop across the orifice 86 is an exact measure of the corresponding change, due to change in viscosity, which takes place during the same interval in the amount of pressure drop across the orifice 18 for any particular output of the pump A; that is to say, it is an exact measure of the effect of the change in viscosity upon the amount of the pressure drop across the orice 10 produced-by a constant output of the pump A and with the adjustment of the orifice 10 and spring 64' unchanged.

According to this embodiment, the chan-ge taking place in the amount of the pressure drop across the orice 86 is employed to correspondingly modify the amount of pressure drop to be maintained across the orice 10. The compensating .cylinder 19 is thereforek connected, as by a passage 8|, with the discharge conduit 85 at a point on the inlet side of the orifice 8 6 and the compensating cylinder'll is similarly connected, as by a passage 82, with said discharge conduit 84 at ajpoint on the outlet side of said orifice 86. The compensating cylinders 19 and 80 are thus*` supplied with `fluid having the same pressures as the pressures existing on the inlet Y and outlet sides respectively of the orice 86.

Two additional opposing forces are thus brought to bear upon the valve piston 60' by the compensating pistons. These two opposing `forces have a net diiierence or resultant tending to move the valve piston 60' toward the right, this net difference or resultant corresponding to and varying with the amount of the pressure drop existing across the orifice 86. The net effect, therefore, is that of-a force tending to move the valve piston 60' toward the right and'which varies conformably with the amount of the pressure drop across theorice 86; hence 4likewise varies with the viscosity of the fluid.

The net difference or resultant of forces thus exerted upon the valve piston 60' by the compensating pistons combines with the force exerted by the spring 64' to determine the amount of pressure drop to be maintained across the in the amount of said net difference or resultant.4 The amount of the pressure drop to be maintained across the orifice 16 is thus modified conthe forces tending to move the valve piston toward the right and those tending to move it toward the left. The relative balance of forces acting upon the valve piston Gf is therefore undisturbed by change in viscosity of the fluid.

Change in viscosity thus affects the amount of pressure drop to be maintained across the orifice 18, and alters the amount thereof in exact accordance with the effect of such change in viscosity upon the amount of the pressure drop actually taking place across the orifice 10 with theoutput of the pump A constant and the ad- 1 justment of 'the spring 64 unchanged. The

compensating mechanism therefore cooperates. with the other parts of the mechanism to hold substantially constant the volume of operating pressure fluid passing through the orifice 16 to the outer ends of the motor vanes I1 and hence to hold the speed of the motor B substantially constant irrespective of change in viscosity of the circulated fluid. The difference in pressures between the operating pressure fluid and the differentialhigh pressure uid will vary, however, with change in viscosity of the c irculated fluid and the spring 64' is accordingly made such that the drop across the oricel10, and hence the difference in pressures of the operating pressure fluid and differential high pressure fluid, is sunlcient to provide satisfactory action of the motor yvanes I1 when the pressure drop across the orice 86 is minimum for the particular fluid employed. This provides satisfactory operation of the motor at all times and with all viscosities of the fluid.

In order to prevent leakage of uid from the valve bore 56' into the compensating cylinders 19 and 80, which leakage might possibly affect the pressures existingv in said compensating cylinders, .the members 15 and 16 are provided with counterbores or-leakage grooves 81 and 88 respectively, intermediate the ends of the valve bore 58" and the exposed ends of the compensating pistons, and said leakage grooves are appropriately connected with the exhaust passage- 59 which leads to the reservoir 41.

When the discharge conduit 85 of the compensating circuit is relativelyl short land -dis- Q charges directly into the reservoir, as illustrated orifice 10 which is', therefore, modified by change formably with the change in viscosity of the fluid and in exact accordance with' the change occury ring in the amount of lt-hefpressure drop across the orifice 10, with a constant 'size of openingV duces the amount of pressure drop across the 1 in Fig. 2, it has been found that the pressure existing on the outlet side of the vorifice 86 is so small and subject to such minor variations that in practice it may frequently be neglected and the amount of pressure existing on the inlet side of the orifice 86 alone employed as of the pressure drop thereacross. In such instances, the compensating cylinderv and its fluid connections may be omitted. Y

Compensation for change in viscosity of the circulated fluid may also be accomplished without modifying the amount of' pressure drop to be maintained across the metering orifice but by modifying the size or extent of lopening thereof,

the measure so that not only will the speed of the motor B be held substantially constant but the dierence in pressures between the operating pressure uid and the `differential high pressure uid will also be maintained substantially constant irrespective of viscosity changes. This may be accomplished, 'for example, by substituting for the orice 'l0 of Figs. 1 and 4 the modified orifice and arrangement illustrated in Fig. 5, and also disclosed in said Patent'No. 2,238,061.

` The metering orice of Fig. is adapted to be substituted for the variable orice of Fig. l, and also A.the variable orifice 'I0 of Fig. 4 as will belater explained. It is shown as of the conventional balanced piston valve type and includes the usual valve piston 90 slidably tted within the bore of the valve housing 95. The conduit 42 is connected with' the valve bore through a pair of. spaced annular ports 91 and 98 respectively and, asindicated bythe arrows,

uid entersthevalve bore through the port 91 and passes out through the port 98.

j The valve piston 90 comprises a pair of heads 9 and 92 separated by a reduced portion which i: preferably tapered to provide gradual opening and closing of the orifice and thus facilitate adjustment. The size ofthe metering vorifice is varied by/axial movement-of the valve piston 90 in the valve bore, this movement varying the extent to which the head 9| restricts communication between the port 91 and the portionof the valve bore leading to the port 98. The arrangement is such that' the valve piston may be moved to any desired extent so that the size or extent 0f opening of the metering orice may be infinitely varied from its` maximum open position to the fully closed position in which the h ead 9| completely cuts off communication between the port.

91 and the valve bore. The reduced taperedportion intermediate the heads 9| and 92is made of such length that the head 92 does not restrict the cylinder port 98 at any position of adjustment of the valve piston 90.

ingly provided with a slot |06 for slidably, receiving a fulcrum block which is rotatable upon a` fulcrum pin as indicated by the dotted lines at |01.

The fulcrum pin is carried by a preferably forked fulcrum bar |08 which is slidably supported by any suitable means, not shown, upon a supporting member |09. The fulcrum bar |08 is also attached to the outer end of the piston rod ||0 of a compensating piston llfreciprocable in a compensating cylinder 2, the piston rod ||0 being guidingly supported by the cylinder cover ||3 through which it projects. A spring ||4 is positioned in the closed end of the compensating cylinder |2 and exerts a forceftending to move the compensating piston inward the right as viewed in Fig. 5.

The compensating cylinder ||2 is connected with an auxiliary or compensating circuit identical with that of Fig. 2 and including a constant capacity pump 83 receiving its supply of uid through a conduit 84 from the same source of supply as that of the fluid passing through the metering orifice in the valve bore.

1A spring 93 is positioned in the closed lower end of the valve bore and acts to move the valve piston 90 upwardly as far and as rapidly as permitted by the other parts of the adjusting mechanism. The upper end of the valve piston 90 bears against the adjacent end of a plunger rod |00 which projects through and is slidably supf ported by the cover 96 which closes the valve bore. In order to assure quick and veasy movement of the valve piston 90 and -to prevent disturbance of its position in the valve bore by the action of unequal fluid pressures on the ends thereof, the portions of the valve bore axially beyond the ends of the valve piston 90 are provided with a fluid connection, such as the passage 94, and the closed lower end of the valve bore is connected with an exhaust passage 99 which may lead to the reservoir 41.

The outer end of the plunger rod |00 slidably bears against an ladjusting -lever |0| by whichA the position of said plunger rod |00, and hence..

the-position of the valve piston 90, are determined. One'end of the adjusting lever |0| isy provided with a suitable handle |02, near which said adjusting lever |0| is pivotally connected as lat |03 with a member which maybe moved along a curved locking bar |04 and which may beheld or fastened at any desired position'on said locking bar 04 by the friction gripping mechanism illustrated atu|05.l The other end of the adjusting lever "|0| is adapted to be supported upon a movable fulcrum andfis accord- The auxiliary or compensating `circuit also includes a variable orice 86 inthe pumps discharge conduit 85, and the forward or piston rod end of the compensating cylinder ||2 is connected with said discharge conduit at a point on the inlet side of the inlet side of said orifice 86 while the rear or closed end of said compensating cylinder I2 is connected with said discharge conduit 85 at a point on the outlet side of the orice 86, these `connections being provided by the passages 8| and 82. y

With this arrangement pressure uid from the inlet side of the orifice 86 exerts a force upon the compensating piston |I| which isvopposed by the combined -forces exerted upon the-other side of the piston by the spring 4 and iiuid from the outlet side of the orice 86. When the pump 83 is driven at a constant speed, the pressure drop across the orice 86 will vary, as herelnbefo e explained, conformably with change in viscosity of the circulated fluid, so thatthe force acting to hold or move the compensating piston against the force exerted by the spring 4 will vary correspondingly. It will thus be seen that the compensating piston and the fulcrum pin will be moved toward the right upon decrease in viscosity of the circulated fluidand toward the left upon increase in said viscosity, the extent of this movement corresponding to the extent of change in viscosity.

Such movement or change in position of the fulcrum pin causes the adjusting lever |0| to rock about its pivot |03, which in' turn results in change in position of the valve piston 90 in the valve bore, thus modifying the size or extent of opening of themetering orifice. In other words, upon decrease in viscosity of the iiuid the compensating piston and fulcrum will move toward the right, as already stated, thus moving ,thevalvefpiston 90 downward and reducing the extent ci opening 'of themetering orifice; in-

crease in viscosity produces action reverse t that just explained and the extent 4of opening of the metering orifice is increased. The dotted lines of Fig. 5 show, to. somewhat exaggeratedextent, the relative positions to which the parts will move from their positions4 as shown' in full linesnpon decrease in viscosity of the uid.

` Change in resistance to ow caused by change in viscosity of the fluid is thus oiset and bal- "l anced by modifying the extent'of opening of theft4 variable metering orifice to oppositely changethe resistance to flow presented thereby.v It will therefore be seen thatl with proper proportions of the parts, the size or extent of opening of the metering orifice may be modified conformably with the e'iect produced by change in viscosity of the uid so that the output of the pump A will not be affected thereby, when i the arrangement of Fig. is substituted for the variable orifice of Fig. 1, and the volume of operating pressure fluid going to the outer ends of the motor vanes |1, and hence the speed of the motor B, will be likewise held substantially constant irrespective of viscosity change. AtI the same time, the difference in pressures between the operating pressure fluid and the differential pressure fluid will also be held substantially constant at the amount determined by the springl 64. It will further be noted that the modifying action to compensate for viscosity change does not affect the position at which the pivot |03 is fastened upon the locking bar |04, so that there is a definite and unchanged speed of the motor B (internal leakage within said motor being again neglected) y for each position of adjustment of this manually movable member.

The orifice 80 is preferably not adjusted during operation but, as is also the case in the embodiment of Fig. 2, its variable feature makes possible the use of the ysame compensating mechanism with almost all fluids. A non-differential piston may be substituted for the compensating piston (Fig. 5) although the differential areas of the pistons ends resulting from the piston rod, in the arrangement shown, will be satisfactory in most instances because the pressure acting on the big end thereof is usually negligible, as it is the same as the pressure existing on the outlet side of the orifice 86; in fact, connection between the closed end of the compensating cylinder and the outlet side of the orifice 10 may be omitted entirely in many instances withoutadversely affecting the operation and control provided by the mechanism.

A variable capacity or delivery pump, as shown' in Figs. 1 and 2, is preferably employed as the source of pressure uid for operation of the moof the valve housing |2| and is provided with a pair of spaced heads ||9 and |20 respectively. The bore of the valve housing |2| is provided with an annular port |22 which is connected with the conduit 42, as-'by the branch passage 42', and which is adapted to be completely Aclosed to prevent all escape of fluid therethrough when the valve piston ||8 is in the position shown, in which the head |20 covers said port |22. The arrangement is such that movement of the valve piston ||8 toward the right as viewed in Fig. 3 progressively opens the port |22 and permits correspondingly increasing amounts of fluid to escape from said port |22, and hence from the conduit 42, the escaping fluid passing around the reduced portion of the valve piston ||8 intermediate its heads ||9 and |20 and to the reservoir 41 through the passage 59'. The head I9 serves principally as a guide and support for `the valve piston as amount of fiuid permitted to `escape is entirely controlled by the extent of opening of the port |22 by the head |20 which. is here shown as provided with conventional V- notches to facilitate the establishment of gradual The operation of the piston 50, for example, is

tor B, the output of said pump being altered to vary and control the speed of said motor as already explained. A constant capacity pump with means for regulating the extent -of escape or bypassing of uid delivered by said pump may, however, be employed instead of the variable dehvery pump A and its output varying means. This will be understood from Fig. 3 which shows, by way of example, and in partly schematic arrangement, a constant capacity pump A and controlled escape or bylpass means in association therewith which may be substituted for the pump A and its output varying means in the arrangement of Figs. 1 and 2, including the modified arrangement of Fig. 1 in which the metering. orifice mechanism of Fig. 5 and its viscosity compensating mechanism are substituted for the orifice 10.

Referring to Fig. 3, lthe pump A' receives its supply of fluid from the reservoir 41 through.,

the conduit- 46 and discharges its pressure fluid into the conduit 42 leading to the motor B '(not shown in Fig. 3) and identical with the' 'con-- duit and arrangement of this portion yof the embodiments illustrated inFigs. land 2 The piston rod of the adjusting piston E50 is attached, as at-40, tothe piston rod'| |1 of the valve piston l0 of the 'escape valve mechanism.

The'valve piston ||0 is reciprocable in the bore 75 the same as explained in connection with Figs.

1 and 2, said piston being moved toward the right to increase the extent of opening of the port |22 and thereby decrease the volume of fluid passing through the orifice 10 responsiveto a pressure drop across said orifice 10 exceed ing the predetermined pressure drop thereacross, and vice versa. The arrangement therefore functions to so control the amount of fluid escape permitted through the port |22 that the Volume of operating pressure, fluid passing to the outer ends of the motor vanes |1 is held substantially constant for any size or extent of opening of the orifice 10, this likewise being true ir\ respective of viscosity changes when the arrangement of Fig. 3 is substituted in Fig. 2. The speed of the motor is regulated by varying the extent of opening of the orifice 10, exactly as explained in connection with Figs. 1 and 2. A stop |25 is preferably provided, however, adjacent the head I9 and adapted to strike the end cover |26, to limit the distance toward the left to which the piston 50 may be moved in order to prevent movement of the valve piston ||8k to a point where the head |20 is `to the` left of the port |22 suiciently to open said port to the right hand end of the valve bore. Fig. 3 shows a portion of the conduit 84 of .the compensating circuit of Fig. 2 which, of course, is connected with the pump 83 when the arrangement of Fig.

2 or Fig. 5 is employed, the conduit'84 beingA omitted when the pump A' and its associated' however, it is frequently simpler and.'4 therefore in y The borelof the valve housing suitably closed at both its ends and is provided .y

with an annular port |3| which is here shown Vas having two connections with the conduit 42 so that the connected portion of saidl valve bore forms in'eifect a part of said -conduit 42. The valve. bore is also provided with an exhaust port |32 spaced from the port |3| and connected with Slidably fitted within the valve bore is a valve piston |35 having two heads |36 and |31 respectively, of the same cross-sectional area and spaced from each other so that they do not obstruct the flow of fluid throughthe port |3| in any position occupied by said valve piston |35. The head |31, which is provided with conventional V-notches, controls the extent of connection between the ports |3| and |32 ,and the valve piston |35 is movable to establish any degree of connection between said ports |3| and |32 to permit by-passing or escape of all, any part or none of the fluid delivered by the constant capacity pump A'. The valve piston |35 is shown in'Fig. 4 in its positionin which it completely cuts ofbcommunication between the ports |3| and |32 and hence prevents the escape of any iiuid, a small stop |38 projecting upward from the head |36 preventing further upward movement of thevalve piston |35 beyond the fully closed position. The valve piston |35 is, how,-

ever, free to move downward from thev position 'shown in Fig. 4 to establish any degree or extent of connection between the ports |3| and \|32 as already stated.

The valve piston |35 is moved and its position controlled responsive to the pressure drop actu-l desired speed, fromy zero to maximum, that can be produced by the output ofthe pump A'.

The metering orice and viscosity compensatl the exhaust passage 59 leadingvto the reservoir the orifice .10 of Fig. 4. When so modified, the arrangement of Fig. 4 will hold the speed of the motor and the pressure difference between the differential high and operating pressure fluids substantially constant irrespective of viscosityl change.

Each of the embodiments shown and described thus provides accurate and dependable means for regulating the speed of the motor B and some of them are capable of corrective action to compensate for all variations in the motors speed except the variation due to the leakage of iiuid past the rotor I5 and vanes |1 from the motors inlet areas to its outlet areas, which is usually small. In all embodiments, regulation of the speed of the motor B is accomplished by regulating and controlling the volume of operating pressure fluid admitted to the outer ends of the vanes, which volume may be varied at will and will be held substantially constant at the desired' amount. The combined fluid volumes admitted to both the inner and outer ends of the motor vanes, |1 is thus regulated and controlled; for example, in the embodiments illustrated the volume orifice 10 is connected, as by a passage 13 with the lower end of the valve bore in which is positioned a spring |34 which exerts a force supplementing the upward force exerted on the vvalve piston |35 by the action of the pressure fluid from the outlet side of -the orifice 10. It is thus seen that pressure fluid from the inlet side force' -is opposed and balanced by the combined forces of the spring |34 and the action'of the p'essurekuid from the voutlet; side of the orifice The valve piston |35 is thus moved responsive to the pressure drop across the orifice 10 and of differential high pressure liuid supplied or admitted to the inner ends of the motor vanes |1 is proportional to the speed of the rotor I5 (leakage being neglected) and hence'is proportional to the volume of operating pressure fluid admitted orfsupplied to the outer ends of said vanes, so that the mechanism thus effectively regulates and controls the combined fluid .volumes supplied to both the inner and outer ends of said motor vanesY I1, which combined volumes may be varied at will by adjustment of the variable orifice. 'I'he same mechanism employed for controlling the speed of the motor B is likewise utilized to provide a pressure drop in the supply line whereby the difference in pressures is obtained between the diierential high pressure fluid supplied to the inner ends of the motor vanes |1 to urge them into contact with the vane track 26 and the operating pressure fluid supplied to the outer cooperate to provide satisfactory operation at the -desired speed, with manyattendant advantages.

takes a position to permit the escape of just the proper fluid volume so that the volume passingthrough the oriiice 10 will produce a pressure..

drop equal in amount'to the value determined byI -constant amount Vthe, pressure of the operating pressure-fluid. VThe speed of the motor B is regulated byyarying'the'size or extent of opening fofthe oriiice `1li and, as,this may be infinitely varied, themptor may thus be operated at any Important among these advantages are the econ.- omy and simplicity made possible along with accurate and reliable operatingresults. l

It will be understood that the several embodiments of my invention have been described for the purpose of illustrating the operating and construction of the apparatus of my present invention and that changes, some of which have been indicated, may be made without departing from the spirit of the invention.

I claim: I,

1. In a fluid pressure system having a variable delivery pump and a rotary vane type fluidvmotor in the fluid circuit thereof, said vane motor having a rotor provided with a plurality of vanes movable inward and outward thereof and also'havlng a vane track adapted to contact one of the ends o'f said vanes to guide them. in their in and out movement,v in combination, a fluid supply line connecting said pump and said motora flow resistance means insaid supply line, means responsive to the pressure drop across said flow resistance means for controlling. the delivery of said pump, and means for connecting -the opposite lends of said vanes in parallel with the inlet and outlet sides of said ow resistance means whereby the difference in pressures across said liow resistance means urges said vanes into contact with said vane track. ,u 2. In a system of the character set forth, a

fluid pressure supply line, a vane motor in said line, means for establishing dierential pressure vane track to guide said vanes in their in and out movement, means for supplying pressure iiuid from the inlet side vof said orifice to the radially drop in said line including means adjustable at will to determine the speed of operation of said motor, means responsive tosaid pressure drop for maintaining the determined speed substantially constant and means supplying the higher oi' the two pressures of said differential pressure drop to the inner ends of the vanes of the motor.

3. Ina system of the character set forth, a iluid pressure supply line, a vane motor in said line, said vane motor having a rotor provided with a plurality of vanes movable inward and outward thereof and a vane track adapted to contact the outer ends of said vanes to guide them intheir inl and out movement, means for establishing differential pressure drop in said line, means responsive to said pressure drop for regulating volume of fluid admitted to said motor to thereby regulate its speed and means supplying the higher of the two pressures lof said dif.- ferential pressure drop to the inner ends of the vanes of the motor.

4. In a fluid pressure power transmission system, a uld pressure supply line, a resistance mechanism in said supply'line, a vane motor having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof, said vane motor also having a vane track to guide said vanes in their in and out movement, means for supplying pressure uid from the inlet side inner ends of" said vanes to urge said vanes into j contact with said vane track, means for simultaneofusly supplying pressure fluid from the outlet side-of said orice to the radially outer ends of sa'id vanes to cause rotation of said rotor,

- means responsive to the diilerence in pressures on the inlet and outlet sides of said oriilce active to alter the volume vof iiuid supplied to said vanes I delivery pump and a rotary vane type fluid motheir in and out movement, in combination, a ow resistance means'in said circuit, means responsive v to the pressure drop across said ilow resistance means for controlling the delivery of said pump, means for supplying to one of the ends of said vanes tluid having thelhigher of the two presof said resistance mechanism to one `end of said vanes to urge said vanes into contact with said vane track, means for simultaneously supplyingY pressure iluid from vthe outlet side oifsaid resistance mechanism to the other ends of 'saidvanes to cause rotation of said rotor, andr motor speed control means responsive to thediiference resistance mechanism.

5. In a fluid pressure power'transmission f tem, a iiud pressure supply line, ajresistance mechanism in said supply line, ka vane motor havin a rotor provided with a .plurality of vanes movable inwardly and outwardly thereof, said vane motor also having a vane track to guide said vanes in their in and out movement, means for supplying pressure uid` from the inlet side fofsaid resistance mechanism to one end'` ofv said vanes to urgesaid vanes into contact with ysaid vane track, means .for simultaneously supplying pressure fluid from the outlet side of said resures existing on opposite sides of said ow re-A sistance mechanism to urge said vanes into contact with said vane' track and means for supplying to the other of the ends of said vanes iluid having the lower of the two 'pressures existing on opposite sides of lsaid ow resistance mechanism to cause rotationI of said rotor. 1

8.; In' a luid pressure system having a variable 'delivery'.pump'and afrotary vane type uidmotor in the `fluid `circuit thereof, `said .vane motor .having a rotorprovided with a plurality of vanes movable inward andyoutward thereof andv also having a vane' rtrack for guiding said vanes in` i 'their' inand out movement, incombin'ation a uid I in pressures on the inlet and outlet'sid of said j i tor, af'flow resistance means in said supply line.

supply line connecting said pumpand said mopower .means ior.` varying" the delivery of said pump', uuid-pressure' operated control means rec sponsive to the pressurel drop across said ilow resistanceY means, said liluid pressure operated controlmeans' being operativevupon a predetermined pressure drop across said ilow resistance means to holdsaid power means in a ilxed posivtion but upon departuresv therefrom to control the a .power means for varying the ,pump delivery in a direction to.correct for such departures in pressistance mechanism to the other ends of said vanes to cause rotation of said rotor,land means responsive to thel diiferencein pressuresfon the "nues and outlet sides' of'v saidjiresistancefmechanism active regulate f the volume of 'fluid supmeans to correct for change in pressure diiference on the inlet and outlet side of said resistance mechanism due to change in viscosity of the fluid to thereby hold substantially constant the volume plied to said vanes', and viscosity compensating-v", mechanism co-operating vwith said `last namedsure'.drop, means for supplying to one of the ends-of lthe' ':im.ne sof said lmotor fluid having thev higher vofthe two pressures existing on oppositefsides of said flow resistance means to urge said vanes into contact with said vane track and means for vsupplyingfto fthe' othe'rj'ojf.v the ,ends of said vanes-duid havingthe lower ofthe'two pres,-

4sures existing on'opposite sides of 'said` flow resistance meansto cause rotation of tsaid rotor.

j 9, In a uid pressure system having a variable delivery pump and a rotary type uid motor in the fluid 'circuitthereoh said vane motor having a 'rotor provided with a plurality of vanes movable inward and outward thereof and also having va vane track tor guiding said vanes in their in and out movement, in combination a iluid supply line connecting said pump and said motor, a ow resistance means in said supply line, power means for varying thel delivery of said pump, fluid pressure operated control means responsive to the pressure dropv across said ow resistance means,

said fluid pressure operated control means being operative upon a predetermined pressure drop across said ow resistance means to hold said power means in a xed position but upon departures therefrom to control the power means for varying the pump delivery in a direction to correct for such departures in pressure drop, means for supplying to one of the ends of -the vanes of said motor uid having the higher of the two pressures existing on opposite sides of said ilow resistance means to urge said vanes into contact with said vane track and means for supplying to the other of the ends of said vanes fluid having the lower of the two pressures existing on opposite sides of said flow resistance I means to cause rotation of said rotor, and viscosity compensating means for correcting for departures in iluid pressure dropv across said ow sures existing on opposite sides of said ow resistance means to` cause rotation of said rotor;

and motor speed control means responsive to the pressure drop across said flowl resistance means for regulating the volume of fluid passing to said motor so that the volume of said lower pressure iluid supplied to one of the ends of the vanes is maintained at a predetermined and outward thereof and` also having a vane track adapted to guide said vanes in their in and out movement, in combination, a fluid supply line for said motor, a ilow resistance means in said supply line, means for supplying to oney l through the intake area of said motor, means resistance means due lto change in viscosity of the fluid.

' 10. In a fluid pressure system having a variable delivery pump and a rotary vane type fluid motor in the fluid circuit thereof, said vane motor having a rotor provided with a plurality of vanes movable inward and outward thereof and also vhaving a vane track for guiding said vanes in their in and out movement, in combi# nation a fluid supply line connecting said pump t and said motor, a flow resistance means in said in a fixed position but upon departures there-` from to control the power means for varying the pump delivery in a direction to correct for such departures in pressure drop, means for supply- `ing to one of the ends of the vanes of said motor fluid having thel higher of the two pressure's existing on opposite sides of said flow resistance means to urge said vanes into contact with said vane track and means for supplying to the other of the ends of said vanes fluid having the vlower of the two pressures existing on opposite sides of said flow resistance means to cause rotation of Asaid rotor, and viscosity compensating means active to modify the amount of said predetermined pressure drop across .said flow resistance means conformably with change in resistance to ow therethrough due to change in viscosity of theuid.

11. In a fluid pressure system having a ro-` tary vane type iiuid motor in the fluid circuit thereof, said vane motor having a rotor provided with a plurality of vanes movable inward and outward thereof and also having a vaney track adapted to guide said vanes in their in and outmovement, in combination, a iluid supply line for said motor, a ow resistance means for supplying to the other of the ends of said vanes uid having the lower of the two pressures existing on opposite sides of said flowresistance means to cause rotation of said rotor, motor in said supply line, means for supplying to one ,ofv the ends of said vanesuid having the higher of the. twopressuresexisting on opposite sides4 of said resistance means to urge said-vanes into contact with' saidl vane "track \while passing through the'intake area of said motor, means for supplying' to the other of the ends of said vanes fluid having the lower-lof the two presspeed control means responsive to the pressure drop across said flow resistance means for regulating the volume of fluid, passing to said motor so that the volume of said lower pressure fluid supplied to oneof the ends of the vanes is maintained at a predetermined rate of Y flow with the viscosity of the circulated fluid constant, and co-operating viscosity compensating means forl correcting for departures in said last named fluid volume conformably with variation in pressure drop across said ow resistance means due to change in viscosity, including means for adjusting said ow resistance means in response to. changes in viscosity.

13. In a uid pressure system including a constant capacity pump and having a rotary vane typefiuid motor having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof and also having a vane track adapted to contact one of the ends of said vanes to guide them in their in and out movement, incombination, a supply line connecting said pump and said motor, an orifice in said supply line, a uid escape mechanism positioned in said supply line and having an element subjected to the pressures existing on opposite sides of said orifice and active responsive to the difference in suchpressures to regulate the volume of escaping iiuid, means for supplying fluid from the inwardly and outwardly thereof in a substantially radial direction, said motor having intake and outlet areas, said'motor also having a vane track adapted to contact the radially outer ends of said vanes to guide them in their in and out movement, in combination, 'a supply line connecting said pump and said motor, a flow resistance means in said'supply line, auid escape mechanism connected with said- 'supply line intermediate said pump and said resistancev a rotor provided movable inward and outward thereof and also Y means, said iiuid escape mechanism including an element movable responsive to the pressure 4drop across saidresistance means relative to a predetermined pressure drop thereacross and active to regulate the volume .of fluid escaping through said escape mechanism, means for supplying to the radially inner ends of said vanes while they are passing through the inlet area of said motor fluid from the inlet side of said i'iow resistance means to urge said vanes into contact with said vane track and means for supplying to the inlet area of said motor fluid from the outlet side of said ow resistance means to act on the exposed radially outer portions of said vanes and thereby produce rotation of said rotor.

s 15. In 4a iiuid pressure system including a pump and having a rotary vane type uid motor provided with a plurality of vanes movable inward and outward of said rotor in a substantially radial direction, said Amotor having intake and outlet areas adjacent the periphery of said rotor, said motor also having a vane track adapted to contact the radially outer ends of said vanes to guide them in their in and out movement, in

combination, a supply line connecting said pump and motor, a variable orifice in said supply line, a fluid escape mechanism connected with said supply line intermediate said pump and said variable orice and having an element movable to regulate Vthe volume of iiuid escaping therethrough, separate power means for moving said element, fluid operated control means responsive to the pressure drop across said orifice, said iiuid pressure operated control means being operative upon a predetermined pressure drop across saidA oriiice to hold said power means in a iixed position but upon departures therefrom to control the power means for varying the volume of uid escaping through said fluid escape means in a direction to correct for such departures in pressure drop, means for supplying to the radially inner ends of the vanes of lsaid motor while they are passing through the inlet areas of said motor uid from the inlet side of said orifice to urge said vanes into contact with said vane track and means for supplying to the inlet area of said motor fluid from the outlet side of said orifice to cause rotation of said motor.

16. In a iiuid pressure system having a variable delivery pump vand a rotary vane type uid motor in the fluid circuit thereof, said vane motor having a rotor provided with a plurality of vanes movable inward and outward thereof and also having a vane track adapted to contact one vofi v the ends of said vanes to guide them intheir responsive to the pressure drop across said flow resistance means for controlling the delivery of said pump, co-operating viscosity compensating means for correcting for ldepartures in pressure drop across said flow resistance means due to changes in viscosity, and means for connecting the opposite ends of said vanes in parallel with the inlet and outlet sides of said ow resistance having a vane track adapted to contact one of the ends of said vanes to guide them in their in and out movement, in combination, a fluid supply line connecting said pump and said motor, a flow resistance means in said supply line, means responsive to the pressure drop across said flow resistance means for controlling the delivery of said pump, co-operating viscosity compensatingl means for correcting for departures in pressure drop across said flow resistance means due to changes in viscosity, and means for connecting the opposite ends of said vanes in parallel with the inlet and outlet sides of said flow resistance named ow resistance means.

18. In a fluid pressure power transmission device including a source of pressure fluid, a rotary vane type fluid motor operated by pressure uid from said source, said motor having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof in a substantially radial direction assaid rotor revolves and a vane track adapted to contact the outer ends of said vanes, said vanes being urged into contact with said track by action of pressure iiuid on the. inner ends thereof and said rotor being revolved by pressure fluid admitted to the outer ends of said vanes, and means actively responsive to the pressure drop across a single oriiice for regulating the combined volumes of pressure iiuid from said source admitted to both ends of said vanes to thereby control the speed of rotation of said rotor and for supplying to the inner ends of said vanes uid under pressure greater than but correlated with the pressure of the fluid admitted to the outer ends of said vanes.

19. In a fluid pressure power system comprising a source of pressure fluid, a rotary vane type fluid motor operated by pressure fluid from said source and a conduit connecting said source with said motor, said motor having a vane track and a rotor provided with a plurality of'vanes movable inwardly and outwardly thereof, said vanes being urged into operating position in contact with said track by iiuid pressure means, in combination, an orifice in said conduit, separate fluid volume supply control means responsiveto the pressure drop acrosssaid orifice active to regulate the volume of fluid supplied from said source to said mo'tor to thereby control the with the inlet and outlet "sides respectively of said orifice whereby the difference in pressures 20. In a iluid pressure power transmission system including a source 'of pressure uid, a

means whereby the diierence in pressures across said flow resistance means urges said vanes into contact with said vane track.

17. In a uid pressure syster'n having a variable delivery pump and a rotary vane type fluid motor' rotary vane type fluid motor operated by pressure uid from said source, said motor having a rotor provided with a plurality of vanes movable inwardly and outwardly thereof and a vane track, said vanes being urged into operating position in contact with said vane track by iiuid pressure means, in combination, a supply line connecting 'said source with said motor, flow resistance means in`said supply line, means for position in contact with said vane track and y, means for supplying pressure uid from the outpressures across said flow resistance means urges said vanes into contact with said track and iluid volume supply control means responsive to the pressure drop across said now resistance means for controlling the combined fluid volumes admitted to both endsl of said vanes, said control vmeans being operative upon a predetermined drop of pressure across said now resistance means to hold said combined fluid volumes substantially constant but upon departures therefrom to alter said combined iluid volumes in a direction to correct for said departures in pressure drop.

21. In a uid pressure. system comprising a vane type iiuid motor and 'a supply line connected thereto, said vane motor having a vane track and a rotor provided with a plurality of vanes movable inwardly and outwardly thereof, said vanes being urged into operating position in contact with said vane track at least in part by iluid pressure means, in combination, motor speed reg- 1 ulating means for controlling the operation of the motor including means for producing a pressure drop whereby two pressures are obtained in the portions o1'` said supply line at opposite ends of said resistance mechanism and means supplying iluid having the higher of said pressures to one of the ends of said vanes to urge them into operating positionv in contact with said vane track.

22. In a` iiuidpressure system comprising a vane type fiuid motor, a pump supplying pressure fluid for operating said motor and a fluid pressure conduit operatively connecting said pump and said motor, `said motor having a vane track and a rotor provided with a plurality of vanes movable inwardly and outwardly thereof, said vanes being urged into operating position in ,contact with said vane track by iluid pressure means, in combination, a variable orice in said conduit, iiuid volume supply control means responsive to the pressure drop across'said orifice active to control the volume of pressure fluid from said pump admitted to said motor conformably with the size of said orifice, means for varying at will the size of said orifice to alterthe volume of pressure fluid admitted to said motor from-said pump, thereby altering the speed of said motor, means for supplying pressure fluid from the inlet side of said orliice to the inner ends of saidvanes to urge them into operating position in contact with said Vane track and means for supplying pressure iluid fromv the outlet side of said orice to the outer ends of said vanes to cause rotation of the rotor. K

23. In a iluid pressure system comprising a vane type fluid motor, a pump supplying pressure iluid for operating said motor and a uid pres- `.sure conduit operatively connecting said pump and said motor, said motor having a vane track and a rotor provided with a plurality. of vanes in combination, an oriflce in said conduit, motor let side of said oriiice to the outer ends of said speed control means being inoperative upon a predetermined pressure drop across said oriiice but upon departures therefrom being operative to alter the volume of pressure fluid supplied to said motor from said pump in a direction to correct for such departures from the predetermined pressure drop.

24. In a fluid pressure system comprising a vane type iluid motor, a pump supplying pressure fluid for operating said motor 'and a uid pressure conduit operatively connecting said pump and said motor, said motor having a vane track and a rotor provided with a plurality oi vanes movable inwardly and outwardly thereof, said vanes being urged into operating position in contact with -said vane track'by iluid pressure means, in combination, flow resistance means in opposite' sides of said now resistance means to u urge said vanes into contact with 'said vane track while passing through the intake area of said motor, means for supplying to the other of the ends of said vanes fluid having the lower of the two pressures existing on opposite sides of said flow resistance means to cause rotation of the rotor, and motor speed control means responsive to the difference in pressures existing on opposite sides of said ilow resistance means for regulating the volume of iluid supplied said motor from said pump so that the volume of said lower pressure nuid supplied to one of the ends of said vanes ismaintained substantially constant at a predetermined rate of now.

25. In a iluid pressure system including a constant capacity pump and having a rotary vane type` iluid motor provided with a plurality of vanas movable inwardly and outwardly thereof in a substantially radial direction, said motor having a vane track adapted to contact the radially outerends of said vanes to guide them in Y movable inwardly and outwardly thereof; said vanes being' urged into operating position in contact with said vane track by'fiuid pressure meansli,`

,their in and out movement', in combination, a l

supply line connecting said pump and said motor. a flow resistance means in said supply line, a

iluid escape mechanism connected with said supply line intermediate said pump and said resistance means, said uid escape mechanism includ-r ing an elementmovable responsive tothe pres-l sure drop across said resistance means relative to a predetermined pressure drop thereacross and active to regulate rthevolume of uid escaping through said escape mechanismto provide iluid ow at a pretermined rate from the outlet side l of said resistance mechanism, means for supplying to the radially inner ends of said vanes while they are passing through said inlet areas of said motor iluid from the inlet-side of said flow reisistance means to urge said-vanes into contact with said vanetrack and means forsupplying to the. inlet areas of said motor fluid from the outlet side of said flow resistance means to act on theexposed radially outer portions of said`vanes and thereby produce rotation of said rotor.

' l CHARLES M; KENDRICK. 

